Proteolytic Enzymes (proteases) inhibit proteins activation or their fate based on hydrolysis of irreversible peptide bonds. Examples of such inhibition include the designation of positions of proteins inside or outside a cell, separation of proteins from a cellular surface, activation or deactivation of various types of growth factor hormone, cytokine and protease, conversion of agonist of receptor into antagonist, and the like. Thus, the protease serves to control various cell functions in a broad sense, which is achieved by digestion of bio-active materials. Therefore, the functional relation of the protease with life phenomena of all life is remarkably important. For example, deficiency or overexpression of a spatiotemporal protease causes fatal results, such as cancers, arthritides, neurodegenerative diseases, cardiovascular diseases and the like. Accordingly, the pharmaceutical industry concerns such proteases and their matrix proteins as major targets for new drug development to thusly give great interest therein.
Such various functions (roles) of the protease and recently completed different genome projects are introducing active investigations (searches) in the functions of the protease in a cell and in a human body. According to the human genome project, approximately more than 500 genes related to the protease were recognized among human genes. Recently, it is newly known that the protease plays a pivotal role in various types of human diseases, e.g., cancers and dementias, and also give birth to such diseases. For example, matrix metalloprotease (MMP) was recognized as a factor which degrades the extracellular matrix in a cell and in a human body. However, many researches have revealed that such MMP is involved in the cell movement in relation to the signal transfer of integrin and degradation of pericellular matrix. In addition, it has also been found out that the MMP plays an important role in the invasion and metastasis of cancer cells. As a result, various attempts for the new drug development are in progress around huge pharmaceutical companies in the developed countries.
Hence, as such new matrix proteins are found out, a variety of physiological functions of the protease group would be in the spotlight in future, whereby it is expected that new target proteins for new drugs can be found out.
However, no technique has not yet given to analyze the amount of specific protease activated and expressed in a quantitative imaging manner or to non-invasively image the degree of protease expressed in vivo, so associated technique development is in urgent need.
Representative methods of measuring protease being currently used may include a 2-D gel and multilevel liquid chromatography method, enzyme-linked immunosorbent assay (ELISA) method, or the like. Such methods, however, require multi-leveled measurement protocols such that it cannot be efficient to be used in screening many kinds of drugs, like developing new drugs. Moreover, such methods are not possible to be used in the early diagnosis of diseases because they detect the expression of unique protease in humans or quantitatively analyze the amount of expression thereof.
Accordingly, the present inventors have invented such a novel metal nanoparticle by which the expression of a unique protease can be detected in a human body or the amount of expression thereof can be quantitatively analyzed.